Color Temperature
In essence, color temperature refers to the frequency of color that can be measured from any particular light source. The efficiency of our own visual experience, however, can make the idea of color temperature somewhat confusing.

This is because our eyes have the intrinsic ability to adjust to color shifts such that a white piece of paper will appear white regardless of what type of light is being cast on it. However, color shifts can be much more apparent in situations where there are two or more light sources of differing color temperatures, like the relatively yellow light that emanates through the windows of a house contrasted against the blue light of dusk.

Color temperature is measured in degrees Kelvin. The most important thing to remember about color temperature is that the higher the Kelvin number, the more blue the light source.

The following chart illustrates an approximate color temperature scale (figure 1).

Color Balance
Color balance is achieved when a color recording device (like a camera) renders an image close to how the human eye perceives it. White Balance settings, film type, colored filters and gels can all help to assist the device in achieving "accurate" color. Alternately, you can also throw the color balance off to render a different mood or effect to an image.

White Balance
If you shoot with a film camera and want to achieve color balance in a daylight setting, you would use daylight film to match the color temperature of daylight. If you shoot with a film camera indoors with incandescent lighting, you would either choose Tungsten film or place a Tungsten filter over the lens to balance the color temperature. If you are shooting digitally, however, achieving color balance in any lighting situation is just a matter of setting the White Balance (WB) in the camera.

In the diagram to the right, you can see how different White Balance settings can affect the color balance of a shot. Remember that if you can match the color temperature of your light source with the correct White Balance setting, you will get color-balanced, or "neutral" results.

Click on the image to enlarge if you are having trouble reading the text.

To further illustrate how the White Balance function works, we decided to take a series of indoor portrait shots using different color temperature settings. We started by taking a snapshot with a point and shoot digital camera.

Daylight WB with Flash
Since the built-in flash of any camera (film or digital) is balanced to the color temperature of daylight (roughly 5300 degrees Kelvin), we set the White Balance accordingly. (Most digital cameras have a few White Balance settings that you can adjust manually, as well as an Auto setting.)

We activated the flash, set the camera to Program (automatic exposure) and took a shot of our model in front of a sweep of white background paper (figure 3).

Although the color temperature is balanced in Figure 3, it also reveals the common problems you get from this type of on-camera flash lighting. Since our light source (the flash) is small and positioned just above the camera, the result is both dimensionally flat and high in contrast. The eyes look darker than they actually are, the reflections in the eyes are unnaturally centered and tiny, and there is a distracting shadow is rendered behind the model's head.

Daylight WB with Continuous (Tungsten) Lighting
To improve the lighting, we decided to light the model with a large diffused, light source for a more natural-looking effect. We also decided to use the Olympus EVOLT E-510 to demonstrate its various White Balance settings. For this next shot, we set up a large soft box attached to a continuous lighting unit and light stand and positioned it to the right of our model at approximately 45-degrees. The light we were using uses a 1000-watt Tungsten lamp that's color-balanced to about 3200-degrees Kelvin, about 2100 degrees warmer than daylight or flash.

For comparison purposes, however, we decided to use the same WB setting as before (5300K: Daylight). In order to select this White Balance preset, first press and hold down the small WB button at the back of the camera and then turn the Control dial to select the SUN icon (figure 4).

Once the lighting was in place, we made a few more adjustments to the camera. Since we wanted the model's eyes to be in sharp focus and for the background to be relatively soft, we set the Exposure and Focus modes to Manual, opened the aperture up to f/4 (the wider the aperture, the more selective the focus), and set the shutter speed to 1/60th of a second to render a good exposure. We then set the ISO to its lowest setting (100), set the Resolution to RAW, focused and took a shot (figures 5 & 6).

To learn more about adjusting these settings, check out the EVOLT E-510 Basic Startup lesson located on this site.

The result shows a tremendous difference in the lighting of the shot. The soft box from the lighting unit had diffused the light to render a soft, wrap-around light on the model's face. The effect is that of a window light. And since the lamp in the lighting unit is continuously on (not a strobe), it forces the model's pupils to close down to reveal more color in his irises. Notice the natural-looking catch-light in his eyes as compared to figure 3.

The color of the shot, however, is much warmer than in figure 3 because the camera recorded the relatively warm light from the Tungsten light (3200K) at a cooler daylight/flash setting (5300K). Remember, the lower the color temperature, the more yellow the light (see charts above).

The closest WB Preset option in the E-510 to balance the color temperature of the Starlite Kit (3200K) is the LIGHTBULB (Tungsten) setting, balanced at 3000K. While 200 degrees Kelvin may not seem like a lot, it can noticeably throw off your Color Balance. To get a closer White Balance setting with the EVOLT E-510, you have two options:

OPTION 1: Custom White Balance
If you know the color temperature of your light source, you can select a specific Kelvin number in 100K increments using the CWB (Custom White Balance) option.

To do this, simply press and hold down the WB button on the back of the camera, turn the Control dial to select the CWB option, press and hold the +/- button next to the Shutter button, and spin the Control dial to select a specific color temperature.

Press the Up or Down arrow keys until you reach the One Touch WB option and then press OK twice to exit the menu(figure 10).

Your Function button will now be set to the One Touch WB option.

Recording a One Touch WB setting
To use the One Touch function, first press the WB button on the back of the camera to activate the White Balance menu and use the Control Dial or arrow keys to select the One Touch WB option (figure 11).

Next, point the camera at a white piece of paper or neutral gray card (photo supply stores carry these in various sizes) and fill the frame. Make sure that your exposure settings will allow you to capture a good exposure (one that's not too light or too dark).

Press and hold down the Fn (Function) key on the back of the camera, and then press the shutter button all the way down to record a White Balance setting. If the exposure is good, the screen will prompt you to record the setting. If you're happy with the capture, press OK (figure 12).

Once we had captured a One Touch WB setting, we took another exposure of our subject (figure 13).

In the result, notice how the model's skin tone looks more natural and that the blue in his eyes is truer in color. Remember to use the One Touch WB setting in situations where you don't know the exact color temperature, as it will guarantee you perfect color balance.

White Fluorescent WB with Continuous (Tungsten) Lighting
To illustrate other Preset WB settings against this Tungsten light source, we first switched the preset to White Fluorescent, measured at 4000K, which is relatively green (figures 14 & 15).

Notice how the colorcast resulted in a strong magenta. Again, this is because when the camera is set to 4000, it is in effect ready to neutralize light with a relatively green cast to it. Think of the camera as adding a specific color to neutralize the color of the light source.

Yet when it captures light that lacks the green cast, it is stuck with an image that is, in effect, recorded with a magenta filter over its lens. The color wheel below illustrates these complementary colors (figure 16).

Shade WB with Continuous (Tungsten) Lighting
Finally, we took a shot at the SHADE setting (7500K), which would be a good setting to use in the shade of a sunny day. The shade of a sunny day is actually slightly bluer in temperature than that of an overcast day (6500) because the ambient light coming from the sky is blue on a sunny day, rather than gray (relatively neutral) on a cloudy day (figures 17 & 18).

Notice how warm the shot is now! The White Balance setting is about 4300 degrees cooler than that of the Starlite, making the result extremely warm. And although the color temperature in this image is not rendered "correctly", it does give the shot a different mood. In fact, this image ended up being one of the model's favorites.

Our model stood with the sunlight raking across the side of his face and we set the camera on a tripod and framed up the shot (figure 19).

Since we were shooting outside, where the color temperature is roughly 5300K at midday, we should have used the 5300 Preset WB setting to match it. But for comparison purposes, we decided to first set the WB to the Tungsten preset (3000K), which, as demonstrated above, is designed to color balance continuous Tungsten light sources.

Since we wanted the model's eyes to be in sharp focus and for the background to be relatively soft, we opened the aperture up to f/4 (the wider the aperture, the more selective the focus). We then set the shutter speed to 1/500th of a second to render a good exposure, focused and took a shot (figures 20 & 21).

Notice how blue the result is! With the White Balance dialed to LIGHT BULB (3000K), the camera was set to record our subject illuminated with Tungsten light. But since our model was lit by the relatively cool light of the sun (review figure 1), the result looks as though a blue filter had been placed over the lens. Keep in mind, however, that shooting at an "incorrect" color setting can sometimes render an interesting look.

At this point, we had a few options for achieving color balance. We could dial the White Balance to the 5300 Preset, manually select a Custom WB setting in 100K intervals, or we could create a One Touch White Balance setting. Here, we opted for the One Touch, since we didn't know the exact color temperature and wanted to achieve exact color balance (figures 22 & 23).

Now the color in our result is much more natural looking. However the lighting of the shot is very high in contrast. Notice how the sun rakes sharply across the model's face. In order to soften the sunlight, we attached a 42" Translucent LiteDisc reflector to a LiteDisc Holder, secured it to a LiteStand, and positioned it in between the model and the sun.

While this softened the light falling on the model, it also reduced the level of light falling on him by 2 full f-stops. To compensate for exposure, we slowed the shutter speed to 1/125th of a second and took another shot (figures 24 & 25).

Notice the differences in the result shot. The contrast has been cut way down and we are now able to make out the details of the model's eyes. Also notice that the gray wall has lightened a full two f-stops due to the change in shutter speed.

To illustrate other Preset WB settings against daylight, we then switched the One Touch WB setting to the White Fluorescent preset, measured at 4000K (relatively green), and took a shot (figures 26 & 27).

Notice how the color cast resulted in a strong magenta. Again, this is because when the camera is set to 4000, it is in effect ready to neutralize light with a relatively green cast to it. Think of the camera as adding a specific color to neutralize the color of the light source.

Here's the color wheel again to illustrate these complementary colors. When the camera captures light that lacks the green cast, it is stuck with an image that is, in effect, recorded with a magenta filter over its lens (figure 28).

Afterward, we switched back to the One Touch setting and decided to make a subtle change to the lighting setup.

While the Translucent LiteDisc worked to diffuse the light of the sun, there was also another light source affecting the right side of the model's face: the ambient fill light of the sky to the right of the model. Sometimes a sky fill works beautifully, and sometimes you will want to modify the fill light so that it is either lighter or darker. To lighten the fill, you might try positioning another LiteDisc reflector, either White or Soft-Gold, to the opposite side of the main source to bounce light into the shadows. Or, as was the case here, you may want to create a "negative" fill to increase contrast and a sense of dimension.

To create a negative fill here, we set up a 42" Black LiteDisc reflector and positioned it to the right of the model to both block the ambient light of the sky and to absorb the light passing through the Translucent LiteDisc. Once it was in place, we took another shot with the same settings (figures 29 & 30).

The result shows a nice lighting ratio, particularly for men: diffused light gradually falling off across the face to a subtle shadow along the right side accentuating the lines of the nose, cheekbone and jaw line.

It's good to keep in mind, however, that there is no definitive way to light a headshot. The architecture of each person's face is unique and as such may require a very different lighting approach.

Summary
As with our demonstrations here, we encourage you to experiment with various White Balance settings and lighting techniques in order to better understand how to achieve accurate color, how to create special effects with varying color shifts, as well as how to control contrast.